Reducing dustiness of dusty materials



Patented Jan. 19, 1937 PATENT OFFICE aosa ss aanuoma nus'rmass or nus'rr m'rpams Benjamin E. Harris, Chicago, m. lqo Application July 13,1935,

Serial No. 31,294

21 Claims.

My invention relates to the treatment of dusty material to prevent the dust from rising into the atmosphere when such dusty material is handied. It relates more in particular to an improved process for treating such materials, to an improved product for use in the treatin process, as well as to a novel process for producing the treating material.

It is well known that when dusty materials,

such as coal or coke, for example, are handled, the dust fiies up in a very disagreeable manner, causing all of the surroundings to be dirtied with the dust, and the air becomes so laden with the dust that even at relatively long distances away,

- ,the dust will subsequently be deposited, as, for

example, in the upper part of a building when coal is handled in the basement thereof. I am aware that suggestions have been made for overcoming this disagreeable factor, but as far as I am aware, no treatment heretofore suggested has satisfactorily met the problem.

'The principal object of my invention, there-.

fore, is to prevent thedust, ordinarily contained in such materials, from flying and being taken up by the surrounding air.

will be commercially available for the most satisfactory use.

Other; objects and features of the invention will be apparent from a consideration .of. the

following detailed description. In general, my invention consists in the discovery that glycerine foots, a by-product in the manufacture "of glycerine, may be used to render dusty material substantially dustless by a suitable treatment. I have found that if the glycerine foots is treated in accordance with the following specification, coal or other dusty material may be treated therewith and may subsequently be handled by shoveling it, running it onconveyors or chutes or in any other way, and substantially no dust whatever will rise in. the

atmosphere. The material, for all practical purposes, can be said to be substantially dustless.

The disposal of glycerine "foo heretofore has been a problem for the glycerine manufacturer. As a rule, he is not permitted to run the 5 foots" into the ordinary commercial sewer systems, and even if it were permitted, there would always be the danger of clogging in the system, and the like, even though the product is substantially water soluble. The product cannot be- 10 satisfactorily burned, and dumping it on waste land is also unsatisfactory. Glycerine foots is a black, evil smelling material, varying in consistency from a thin syrup to a tacky solid and, in general, its principal constituents are poly- 15 merized glycerols, which are the substances of principal value in my process, sodium chloride, sulphate, and salts (principally sodium salts) ofvarious aliphatic acids. This material may be used directly by dissolving it in water and spraying it onto the material to be rendered dustless in suitable proportions. In the direct use of .the product, the best results are obtained by dissolving about one pound of the foots" in a gallon of water, and this solution should be 25 sprayed onto the dusty material in proportions of from approximately one-half gallon to four gallons per ton, depending upon the characteristics and condition of the material. Among the materials which can be and have been mm 30 dered dustles, in accordance with my invention, are coke, coke breeze, various types of bituminous or semi-bituminous or anthracite coals, in either the form-of slack, mine run, screenings or prepared sizes. It will be understood readily 35 that straight bituminous slack will require substantially the greatest amount of treatment, while prepared sizes of anthracite coal usually will require a minimum amount of the solution to render it entirely dustless.

I have referred above to thefact that the glycerine foots has an obnoxious odor and it is desirable, for obvious reasons, to remove this odor, if possible. I have found that this can be accomplished by treating the foots", preferably at a slightly elevated temperature as, for example, F., with caustic soda or other strong alkali in proportion of from one half to three pounds for one hundred pounds of foots. This alkali treatment can be carried on in any suitable 5 way. I have obtained good results by first dissolving the caustlc soda in its own weight of water and then incorporating the solution of alkali with the foots".

I have found that, when some types of ma- 55 terial, particularly coal, alkali treated according to the process just described, are permitted to stand for prolonged periods of time, objectionable odors develop. Where such materials are stored in household or factory bins or otherwise,.

this represents an undesirable feature. I have discovered that particularly where prolonged storage conditions are likely to beencountered, it is desirable to subject the foots to a treatment which will eliminate any tendency of the foots to develop objectionable odors even under relatively long periods of storage of coal and other materials which are normally dusty or tend to develop dustiness in handling.

One way in which this result can be achieved is as follows: In an upright iron still or other suitable apparatus, 900 gallons of foots (approximately 9,000 pounds with a moisture contemperature of about 150 F. Approximately 46 gallons of sulphuric acids Baum) diluted with 150 gallons of water are then run into the warmed f00 ts" and the mixture is agitated by a mechanical stirrer or other suitable means. Live steam at a gauge pressure of about 85 p0 ds is then blown into. the footsacid mixtur and the steam distillation is continued in this manner until from about 14,000 to 15,000 pounds of steam have been consumed. Generally, this will require from six to six and onehalf hours, and during this time the average temperature of the contents of the still will be about 240 F. The condensate is a vile smelling,

more or less highly colored liquid which, upon standing, separates into two layers, one of which contains the largest amount of material and is composed of water having odoriferous material dissolved therein. The other layer, which is immiscible with water, varies in weight but, in general, will amount to about two to three hundred pounds of material. The residue in the still, which is now substantially neutral in odor, is then pumped into a cooling tank and. when its temperature has dropped to about 150 'F., approximately 450 pounds of caustic soda, preferably in flake form, are stirred in and the agitation is continued until a homogeneous mass is tent of from 15% to 20%) are warmed to aobtained. The resulting product is a mixture able odors from the foots is not to be construed in a limited sense. The procedure outlined represents merely an examplapf one embodiment" of the invention. The process can be' varied in several ways. For example, the distillation can be carried out with superheated steam, or-with steam or superheated steam in a vacuum. In this latter case, lower operating temperatures may be employed. The process may be varied also by the employment of other.

strong acids in place of or in addition to the sulphuric acid. In this connection, the mineral acids such as hydrochloricacid may be satisfactorily employed. Similarly, alkalies other than caustic soda may be utilized in place of or in addition to caustic soda. Caustic potash and soda ash areillustrative examples of alkaline material which is quite suitable for the purpose.

Additionally, it will beunderstood that the'pro- -herewith listed.

portions of acid may be varied depending upon the particular acid employed or the specific character of the results sought to be obtained. Where varying proportions of acid are used, it will be apparent that the amount of alkali will be correspondingly varied.

Inasmuch as the treatment of coal, for example, usually takes place in an open yard where the temperature at times will be extremely low, I- have found it advisable to suppress the freezing point of the solution, so that even in the coldest weather, the solution can be sprayed onto the coal. This is accomplished by using any suitable freezing point depressant, such as ordinary sodium chloride, sodium nitrate, potassium chloride, etc., unless, of course, unusually low temperatures are to be encountered, in which case other freezing point depressants, such as calcium chloride or magnesium chloride, or mixtures thereof may also be employed.

A particularly effective freezing point depressant for this purpose is a calcium chloridemagnesium chloride product prepared from natural brines by evaporation of the water therefrom. It has been proposed to employ this (hygroscopic) salt product in connection with coal for allaying dust. While somewhat effective for this purpose, it possesses various disadvantages, among which may be mentioned the corrosive effect of the product upon metal surfaces such as shovels, chutes, etc. which are employed for handling the coal and similar products. I have found that a mixture of the foots, treated or not as heretofore described, with this calcium chloride-magnesium chloride product, will allay dust very effectively and at the same time materially reduce the corroding action of said salt product. This result is extremely beneficial in that it enables the efi'ectuation in a very simple manner of the combined eflects of dust allaying and substantially complete reduction of corrosive action, and the ability to utilize the product under conditions of extreme cold. Some illustrative mixtures which have been used with excellent results are Parts A. CaClz-MgClz 1025 NaCl 7'75 Treated foots 200 B. CaClz-MgClz 875 NaCl 525 Treated foots 600 C. CaClz-MgClz 1025 NaCIi 715 NaaCOa (soda ash) 60 Treated foots 200 These illustrative mixtures are employed in the same manner that the mixture of salt and foots is utilized as hereinafter described.

The use of a freezing point depressant, such as salt, permits me to prepare the glycerine foots in a most desirable manner for deliveries through the usual avenues of trade. I am able to prepare the product in. a substantially dry form which can be shipped in bags, drums or barrels, and the following specific example of the practice of the invention is sufliciently illustrative of the advantages secured.

The glycerine "foots" is first treated with the caustic soda, potash or other strong alkali, in

A solution with the material. In the treating of the glycerine foots, a substantially different common salt in the proportion of one part of the "foots to three'parts'of salt. It will be understood that the steam distilled glycerine foots as well as the untreated foots can also be admixed with frezing point depressants to produce substantially dry products in the same manner. I have found that the best results are obtained if kiln-dried granulated salt is used for this purpose. The resulting mixture of the salt and treated foots is a somewhat moist, but mealylike, substance resembling, very much, ordinary brown sugar in both color and consistency. This product is available for shipment in moisture-proof burlap bags, for example, or other suitable containers.

In using the prepared foots product, it is v dissolved in water in proportions of one hundred pounds of foots to approximately twentyseven or twenty-eight gallons of water. This produces about thirty-four or thirty-five gallons of a solution, the freezing point of which is suppressed to such an extent that the solution will not commence to freeze until about 10 degrees illustrative, as there may be times when less of the. solution will be sumcient for the purpose. and other times possibly in which somewhat more may be employed with satisfaction.

For best results, precaution should be taken to obtain an intimate mixture of the ftiots" coal or coke, for example, the spraying can .be

carried out while the coal is being moved, eitherwhen the maximum surface of the coal is available for contact with the spray.

A very great advantage. from the use of my process is that after treatment of combustible material such as ordinary bituminous coal with product results and the coal has burning characteristics which the same coal untreated does not possess. The combustion is very much more complete than otherwise, with a given fuel, there is much less accumulation of soot and fly-ash, and the flues do not require such frequent cleaning as when untreated fuel is used.

Although I have described my invention in detail to permit those skilled in the art to prac-. tice the same, it is obvious that I do not restrict myself to the details described. the invention being limited only by the scope of the appended claims.

Thisjapplication is a continuation-impart of my application, SerialN'o. 575.158, filed November 14, 1931.

' What I claim as new and desire to protect by 1. The method of reducing dustiness of coal,

coke, or the like dusty material which comprises spraying such material with an aqueous solution of glycerine foots.

' 2. .A method of reducing the dustiness of coal, coke or similar material which is normally dusty or has a tendency to lorm dust in handling, comprising, preliminarily removing objectionable odors or substances having objectionable odor forming tendencies from glycerine foots by a steam distillation treatment. and intimately contacting the coal, coke or similar material with a relatively small amount of the treated foots".

3. The method of reducing the dustiness of coal, coke, or the like dusty material, which comprises forming a-solution of glycerine "foots, water and a freezing point depressant, and spraying the material with such solution.

4. A method of reducing the dustiness of coal, coke, or the like dusty material, which comprises mixing glycerine foots. with a relatively small amount of strong alkali, forming a solution of the resulting mixture with water and spraying the dusty material with the solution.

5. A method of reducing the dustiness of coal, coke or similar material which is normally dusty or has a tendency to form dust in handling, comprising, intimately contacting said material with a relatively small proportion of an acid treated, steam distilled, and alkali treated glycerine ffoots prdduct.

6. The method of reducing dustiness of coal, coke or the like which comprises forming a solution of glycerine "foots in water and spraying the dusty material with such solution while the coal is being separated to expose the maximum amount of surface thereof to the solution.

'7. A fuel having a tendency normally to developdust during the handling thereof, intip mately admixed with ,a relatively small amount of glycerine foots", whereby the tendency to form dust is effectively reduced.

8. A fuel havinga tendency normally to develop dust during the handling thereof, intimately admixed with a relatively small amount of glycerine foots and a freezing point depressant, whereby the tendency to form dust is effectively reduced.

9. A dust preventive composition for the treatment of coal, coke or similar dusty or dust forming materials, comprising a solution of glycerine foots in water, the glycerine foots being present in proportion suflicient to efiectively reduce the dustiness of said materials when applied thereto.

10. A dust preventive composition for the treatment of coal, coke and like dusty material, comprising a solution of steam deodorized glycerine foots in water, the foots being present in proportion sumcient to eifectively reduce the dustiness of said material when applied thereto.

11. A dust preventive composition for the treatment of coal, coke or similar dusty or dust forming materials, comprising a solution of glycerine foots" in water and an added freezing point depressant.

12. A dust preventive composition for the treatment of coal, coke or similar dusty or dust forming material, comprising a mixture of glycerine foots and an added alkali 13. A dust preventive composition for the treatment of coal, coke and like dusty material, comprising a mixture of a substantial roportion of glycerine foots" and a freezing po t depressant, the freezing point depressant. being present in an amount sumcient to produce a composition having a substantially solid form.

14. A dust preventive composition for the treatment of coal, coke and like dusty material, comprising an acid treated, steam distilled and alkali treated glycerine fots" product.

15. A dust preventive composition for the treatment of coal, coke and like dusty material, comprising a mixture of steam deodorized glycerine foots and'a freezing point depressant, said composition being in substantially dry form.

treatment of coal, coke and like dusty material,

said composition being in substantially dry form and containing the following ingredients in the following proportions:

Parts Calcium chloride-magnesium chloride 875 to 1025 Sodium chloride 525 to 775 Steam distilled glycerine foots" 600 to 200 19. A method of treating glycerine foots to produce a dustpreventive composition which comprises mixing a relatively strong acid with said foots, subjecting the mixture to steam distillation, cooling it and admixing therewith caustic soda to produce a substantially homogeneous mass.

20. A method of 'treating glycerin foots to produce a dust preventive composition which comprises mixing a relatively strong acid with said foots", subjecting the mixture to steam distillation, cooling it and admixing therewith an alkaline material to produce a substantially honmogeneous mass. 21. A method of treating glycerin facts to produce a dust preventive composition which comprises admixing approximately 900 gallons of foots having a moisture content of between about 15% and 20% with approximately 46 gallons of 60 Baum sulphuric acid and 15d gallons of water, injecting live steam at a gauge pressure of .about 85 pounds into the mixture for several hours whereby it is subjected to steam distillation, cooling the residue, adding about 450 pounds of caustic soda, and stirring the mass until it becomes substantially homogeneous.

BENJAMIN R. HARRIS. 

